1. Field of the Invention
The present invention relates generally to cellular communication systems, and more specifically to cellular control signals transmitted between a base station controller and a cell-site base station.
2. Description of the Related Art
In a cellular communication system, a base station controller is connected to a cell-site base station via a plurality of transmission lines and cellular control signals are multiplexed onto a specified one of the transmission lines and transmitted with payload signals in a multiplex format. Such control signals include a maintenance signal designated "embedded operations channel (EOC)" and a mobile control signal designated "system broadcast channel (SBC)". However, no protection switching is provided for the transmission lines. If a failure occurs in such a specified transmission line, the cellular control signals will be lost, resulting in an outage of the whole system.